The invention is directed to a low emissions one part adhesives and methods of making the same.
The invention relates generally to adhesives, such as flooring adhesives, and more particularly, to adhesives that have low emissions of undesirable materials, such as volatile organic compounds (VOCs).
Many products are assembled using adhesives. For example, various flooring products made from wood, vinyl, tile, carpet and so forth are permanently adhered to a surface or substrate through the use of an adhesive. Commonly used adhesives include those sold under the trademarks Taylor Enviotec 2090 Vinyl Adhesive and Taylor Envirotec 2055 Premium Carpet Adhesive sold, by W. F. Taylor Co. of Fontana, Calif.
There are at least two general types of adhesives: two component adhesives and one component adhesives. Two components reactive adhesives are generally formed with a resin component and a hardener component and the resin and hardener are mixed immediately prior to application. This causes a chemical reaction to occur which typically initiates some type of cross-linking process. Two component adhesives are often considered undesirable because considerable mixing of the components must occur just prior to use. This can be inconvenient. Also, just the right amount of adhesive must be mixed prior to application. If too much is mixed, or the working xe2x80x9cpotxe2x80x9d time is exceeded, the adhesive will harden and the excess must be discarded. Reactive urethane type adhesives contain materials such as isocyanates, which are often considered undesirable.
Single component adhesives can be more convenient to use than two component adhesives. Many single component adhesives are solvent-based adhesives in which an adhesive composition is mixed with a solvent and packaged in a drum, can or tube. After the adhesive is applied to a substrate, the solvent evaporates, which causes the adhesive to cure.
The solvents used in certain conventional solvent-based adhesives are believed by some to be undesirable. For example, many solvent-based adhesives emit VOCs. Depending on the working environment, available ventilation, and the amount of adhesive to be used, some consider the VOC""s and other emitted chemicals to be disadvantageous. Other single component adhesives contain excessive amounts of water, which can damage wood surfaces. There are other single component reactive adhesives such as moisture cure urethanes, but they typically exhibit emission problems because they give off solvents and other potentially dangerous materials such as isocyantes (MDI and TDI).
Accordingly, it is desirable to provide an improved adhesive which overcomes drawbacks and inadequacies of conventional adhesives.
Generally speaking, in accordance with the invention, a one component high strength adhesive composition which can be formulated to have low or substantially no VOC emissions is provided. Adhesives in accordance with the invention can be formulated as high solids, one-part, reactive, cross-linked adhesives. This can be achieved by utilizing amide-ester-acrylate reactions or reactions with any other carboxylated polymers. Adhesive compositions in accordance with the invention can include oils, such as various drying oils and similarly acting polymers, co-polymers, and fatty acids. Metal naphthanates can be used to catalyze the drying speed when the adhesive composition is applied to a substrate.
Adhesives in accordance with the invention can also include various hydrocarbon resins, particularly crosslinkable hydrocarbons having a melting point in the range 70xc2x0 C. to 140xc2x0 C. These can be dissolved or otherwise mixed in the drying oil component. For example, C-5 hydrocarbon resins formed from hydrocarbons having an average of about five carbon atoms and C-9 hydrocarbon resins formed of hydrocarbons having an average of about 9 carbon atoms and preferably both, mixed in effective proportions to provide desired cured strength, green strength, open working times and so forth can be satisfactory.
Adhesives in accordance with the invention can also include fugitive alkali agents, such as ammonia, monomethanol amine (MEA) and triethanol amine (TEA). Cross linking agents, such as materials with pendant oxazoline groups, such as latex polymer solutions and emulsions which include those groups are also advantageously included. Various other mixing, flow and other handling ingredients can also be included.
High solids construction adhesives in accordance with the invention can be particularly useful in assembling various flooring products made from wood, vinyl, ceramic, rubber to various substrates common to flooring installations including: concrete, plywood, underlayment grade particle board, vinyl, ceramic tile, cement patches and underlayments, radiant heat flooring and terrazzo. Adhesives in accordance with the invention can benefit from polymer emulsions with carboxyl functionality, polymer emulsion cross-linkers containing pendant oxazoline group are also advantageously employed. Other useful ingredients include tackifying hydrocarbon resins dissolved in drying oils; napthanates of metals such as cobalt, calcium, zirconium, and manganese; fugitive bases for pH adjustment; and other stabilizing agents, such as fugitive anti-oxidants.
Accordingly, it is an object of the invention to provide an improved adhesive.
Another object of the invention is to provide an improved method of making an adhesive.
Still other objects of the invention will in part be obvious and will, in part, be apparent from the specification. The invention accordingly comprises the composition of matter, the method of making a composition of matter and the method of using the composition of matter which will be exemplified in the compositions and methods hereinafter described, and the scope of the invention will be indicated in the claims.